I have a Macbook with an external display. I use both displays and when I do a screen capture (⌘ + ⇧ + 3) I get two files on the desktop, one for each display. Is there a way to choose which display to grab the screenshot from when doing the screen capture?
You might use ⇧⌘4 (Save picture of selected area as a file) and just drag the selection around one display.
screencapture -m only captures the main display:
I don't know if -S supposed to capture the display of the selected window, but options like -Sw or -SW only seemed to capture the selected window.
-R (rect) captures a specified area:
Thanks to Lauri Ranta's answer, I made a Keyboard Maestro shortcut. I thought I'd share it so that other people can re-use it.